I can only guess that you are connecting everything thru a switch. With a switch or some dual speed hubs (ish) each port will autonegotiate to the lowest common denominator for that point to point connection. First it will try 100Mb full duplex, then 100Mb half duplex, then do the same with 10Mb. So if you are connecting a switch to a 10Mb hub then the switch will negotiate a 10Mb half duplex connection because the hub is only capable of 10Mb half duplex. When connecting to just about any 10/100 NIC that you could buy today the switch and NIC will negotiate a 100Mb full duplex connection on that port. That same NIC would negotiate a 10Mb half duplex connection with a 10Mb hub. The point is the two speeds do not exist on one cable at the same time. So it looks like the common system you are transfering files to/from (server) is at 100Mb on one switch port, one PC is at 100Mb and the last one is at 10Mb. The 100Mb system talks to the switch at 100Mb and the switch talks to the server at 100Mb. The 10Mb system talks to the switch at 10Mb and the switch talks to the server at 100Mb but using only 1/10th of the available pipe. (If all else is quiet anyway and assuming that the system is capable of filing the pipe.) Dual speed hubs work in a similar fashion but a dual speed hub basically has a 10Mb collision domain and a 100Mb collision domain that are connected thru a 2 port switch. In my opinion this was a half assed slipshod way of doing it and only made sense during the 6-12 month time frame when 10/100 switches were just a little too expensive. I would explain more but I have probably already done severe brain damage to some people with my discombobulated explanation. Even I am bored with me at this point. -----Original Message----- From: Mike Bresnahan [mailto:mbresnah at visi.com] Sent: Sunday, November 18, 2001 4:16 PM To: Tclug-List at Mn-Linux.Org Subject: [TCLUG] Co-living 100mb and 10mb ethernet Could someone explain to me in a nutshell how 10mb and 100mb co-exist happily on the same ethernet? For example, I have 3PCs and a DSL modem on my local network. 1 PC and the modem have 10mb cards and 2 of the PCs have 100mb cards. When I transfer a file from one of the 100mb machines it takes about 5 times less time than when I transfer to the 10mb machine, so it certainly appears that the network is capable of both speeds. Evidently the 10mb is able to detect and handle collisions with the 100mb and vice versa. Perhaps it's because they both use the same carrier frequency; if they use such a thing? Also, is a 5x speed difference what I should expect? Not 10x? Take pity on me. I'm a software guy. Mike _______________________________________________ Twin Cities Linux Users Group Mailing List - Minneapolis/St. Paul, Minnesota http://www.mn-linux.org tclug-list at mn-linux.org https://mailman.mn-linux.org/mailman/listinfo/tclug-list